Hydraulic apparatus for controlling brakes



'Sept. 1o, 1935. G. L. R. J. MESSIER 2,014,339

HYDRAULIC APPARATUS FOR CONTROLLING BRAKES Filed Feb. 1, 1934 Patented Sept. 10, 1935 PATENT OFFICE HYDRAULIC APPARATUS FOR CONTROLLING BRAKES George Louis Ren Jean Messier, deceased, late of Paris, France, by Yvonne Lucie Messier, born Bonnamy, administratrix, Paris, France Application February '1, 1934, Serial No. 709,279 /2 In France February 4, 1933 2 Claims.

The present invention has for its object to assure the semi-automatic control of brakes upon the wheels of landing gears'for aeroplanes.

It isapplied to apparatus in which the brakes upon wheels properly so called are arranged in such a'manner that the flow of liquid under pressure into the apparatus in a direct manner causes the application of the brakes.

- The invention is characterized principally by the combination of parts hereinafter defined:

l, a reservoir of fluid under pressure;

2, a pump body the principal piston of which is connected to the skid of the aeroplane and which may be placed in communication with the devices directly controlling the brakes;

3, a distributing part, operated by the pilot and enabling him to place the controlling parts of the brakes into communication, either with the said pump body or with a reservoir of fluid;

4, an accumulator connected to the said pump body and receiving, a part of the liquid driven back by the piston of the accumulator when the skid is applied to the ground;

5, in the pump body, a second piston which is under the action of an elastic device and which may be pressed back by the principal piston at a certain point in the travel of this latter.

The apparatus comprises likewise a set of. valves permitting either the return of the liquid from the reservoir to the pump body or the rapid return of this liquid from the brakes towards the pump body and the immediate release of the brakes, as soon as the reaction of the ground no longer is felt by the skid, whatever may be the position of the control lever of the distributor.

. Finally a constriction provided upon the tubing connecting the pump body to the brake assists in assuring the progressive action of braking.

The accompanying drawing shows a diagrammatic representation of the apparatus.

The generator part of the liquid under pressure is controlled by the reaction of the ground upon the skid. For this purpose the skid is connected in any suitable manner to the piston 2 of a pump body 3, enclosing a suitable liquid.

When the skid I makes contact with the ground, the pressing inwards of the piston 2 causes the flowing back of the liquid frbm'ihe pump body 3 towards an accumulator 4 connected to the said pump body by tubes 5-6.

The accumulator 4 may be constructed in' any manner. For example, it may be composed of a cylinder in which a movable piston I is displaced when the liquid is fiowingcompressing an elastic device 8, having certain characteristics.

- This elastic device may be a spring, a cushion' of compressed air or any other equivalent device.

When all the liquid has been driven out of the pump body 3, the piston 2 makes contact, for example by a projection 2 carried by it, with a 5 second piston 9, normally retained against a stop plate ill by any elastic device I I At this moment the two pistons! and 9 move together and the elastic device I l assures the elasticity of the skid when running on the ground. 10

A tube l2, branched upon the tubes 5, 6 conducts the liquid under pressure, when the skid presses on the ground, towards'a distributor I3.

This distributor enables the pilot to put the liquid into communication with a tube l4, leading to the brakes F, or with the feed tube l2 or with an escape tube 15 leading to a reservoir IS, in which the air may be retained at atmospheric pressure or at a different pressure.

When the pilot wishes to apply the brakes, he 2 puts the lever L of the distributor I3 into the position a corresponding to the putting into communication oi the tubes l2 and M. In these conditions the braking is proportional to the pressure of the ground upon the skid so long as the pres 2 sure of the liquid does not attain the value-that corresponds with the complete driving out of the liquid from the pump, body 3.

After this instant the pressure does not increase whatever may be the value of the reaction 30 of the ground upon the skid.

Each time that the skid leaves the ground, for example if it happens that the skid lifts during its travel over the ground, in course of landing, the liquid flows back by the tubes H and I2, wards the pump body 3,. and the brakes are released, which reduces the risk of capsizing.

The skid being upon the ground, if the pilot wishes to release the brakes, he puts the leverL of the distributor l3, into the'releasing position 40 12, corresponding to. the placing in communication of the tubes l4 and 15. The liquid from the brakes then passes away towards the reservoir I6.

0n the following flight, a certain quantity of 45 liquid from the reservoir I6, returnsinto the pump body 3 by means of the tube l1 and the valve-18.

This return is facilitated at the same time by the presence of a spring l9, which tends to return 5 the piston 2 towards its initial position and by the decrease of pressure that then exists in the p mp body 3- v t A constricted passage 20 enables the rapidity of putting the brakes into action to be modified,- 55

whilst a valve 2| assures a rapid release of the brakes,-when the skid leaves the ground.

A valve 22, ensures under any circumstances and whatever may be the position of the distributor I3, the return of the liquid from the tube l4, towards the tube l2, when the reaction of the ground upon the skid no longer makes itself felt. All risk of capsizing by untimely braking is thus avoided.

The connection between the skid l and the piston 2 may be effected by a set of cables and pulleys in accordance with that having been the subject of French Patent No. 688,526 dated April 9, 1929.

The valve I8 may be replaced by a feeding device such as that which was the subject of an application for a patent in United States of America Sr. No. 641,305 filed November 4, 1932.

The tube I4 may be either connected directly to the brakes, or on the contrary, it may be mounted so as only to put the brakes in action by means of a control system enabling the pilot either to graduate the intensity of braking, without himself having to furnish the power or to obtain a separated or differential braking effect upon each wheel.

This system of control may be of the type forming the subject of United States Patent No. 1,822,900 dated September 15, 1931.

What is claimed is:

1. Device for the semi-automatic control of brakes on the wheels of landing gears for airplanes, comprising a reservoir of fluid under pressure, a pump barrel the primary piston of which is connected to the tail skid of the airplane, control members directly acting on the brakes for applying them, a communication between said pump barrel and these members, a distributor operated bythe pilot and enabling him to put said control members 'in communication either with the pump barrel or with the reservoir of fluid under pressure, an accumulator connected to said pump barrel and receiving a portion of the liquid delivered by the primary 5 piston when the tail skid ofthe airplane bears on the ground, a secondary piston movable in the pump barrel and which can be pushed back by the primary piston at a definite point of the stroke of the latter, and a resilient system acting on this secondary piston.

2. Device for the semi-automatic control of brakes on the wheels of landing gears 'for airplanes, comprising a reservoir of fluid under pressure,a pump barrel the primary piston of which is connected to the tail skid of the airplane, control members directly acting on the brakes for applying them, a communication between said pump barrel and these members, a distributor operated by the pilot and enabling him to put said control members in communication either with the pump barrel or with the reservoir of fluid under pressure, an accumulator connected to said pump barrel and receiving a portion of the liquid delivered by the primary piston when the tail skid of the airplane bears on the ground, 1 a secondary piston movable in the pump barrel and which can be pushed back by the primary piston at a definite point of the stroke of the latter, a resilient system acting on this secondary piston, and a constricted passage on the main communication so as to transmit to the brakes only the mean pressure furnished by the tail skid without transmitting the slight variations of pressure due to the unevenness of the ground.

YVONNE LUCIE MESSIER,

' BORN BONNAMY, Administratrja: of the Estate of George Louis Ren Jean Messier, Deceased. 

